input.c revision 17987 
1/*-
2 * Copyright (c) 1991, 1993
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * Kenneth Almquist.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 * 3. All advertising materials mentioning features or use of this software
17 *    must display the following acknowledgement:
18 *	This product includes software developed by the University of
19 *	California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 *    may be used to endorse or promote products derived from this software
22 *    without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 *
36 *	$Id: input.c,v 1.4 1995/11/03 18:50:14 peter Exp $
37 */
38
39#ifndef lint
40static char sccsid[] = "@(#)input.c	8.3 (Berkeley) 6/9/95";
41#endif /* not lint */
42
43#include <stdio.h>	/* defines BUFSIZ */
44#include <fcntl.h>
45#include <errno.h>
46#include <unistd.h>
47#include <stdlib.h>
48#include <string.h>
49
50/*
51 * This file implements the input routines used by the parser.
52 */
53
54#include "shell.h"
55#include "redir.h"
56#include "syntax.h"
57#include "input.h"
58#include "output.h"
59#include "options.h"
60#include "memalloc.h"
61#include "error.h"
62#include "alias.h"
63#include "parser.h"
64#include "myhistedit.h"
65
66#define EOF_NLEFT -99		/* value of parsenleft when EOF pushed back */
67
68MKINIT
69struct strpush {
70	struct strpush *prev;	/* preceding string on stack */
71	char *prevstring;
72	int prevnleft;
73	int prevlleft;
74	struct alias *ap;	/* if push was associated with an alias */
75};
76
77/*
78 * The parsefile structure pointed to by the global variable parsefile
79 * contains information about the current file being read.
80 */
81
82MKINIT
83struct parsefile {
84	struct parsefile *prev;	/* preceding file on stack */
85	int linno;		/* current line */
86	int fd;			/* file descriptor (or -1 if string) */
87	int nleft;		/* number of chars left in line */
88	int lleft;		/* number of lines left in buffer */
89	char *nextc;		/* next char in buffer */
90	char *buf;		/* input buffer */
91	struct strpush *strpush; /* for pushing strings at this level */
92	struct strpush basestrpush; /* so pushing one is fast */
93};
94
95
96int plinno = 1;			/* input line number */
97MKINIT int parsenleft;		/* copy of parsefile->nleft */
98MKINIT int parselleft;		/* copy of parsefile->lleft */
99char *parsenextc;		/* copy of parsefile->nextc */
100MKINIT struct parsefile basepf;	/* top level input file */
101char basebuf[BUFSIZ];		/* buffer for top level input file */
102struct parsefile *parsefile = &basepf;	/* current input file */
103int init_editline = 0;		/* editline library initialized? */
104int whichprompt;		/* 1 == PS1, 2 == PS2 */
105
106EditLine *el;			/* cookie for editline package */
107
108STATIC void pushfile __P((void));
109
110#ifdef mkinit
111INCLUDE "input.h"
112INCLUDE "error.h"
113
114INIT {
115	extern char basebuf[];
116
117	basepf.nextc = basepf.buf = basebuf;
118}
119
120RESET {
121	if (exception != EXSHELLPROC)
122		parselleft = parsenleft = 0;	/* clear input buffer */
123	popallfiles();
124}
125
126SHELLPROC {
127	popallfiles();
128}
129#endif
130
131
132/*
133 * Read a line from the script.
134 */
135
136char *
137pfgets(line, len)
138	char *line;
139	int len;
140{
141	register char *p = line;
142	int nleft = len;
143	int c;
144
145	while (--nleft > 0) {
146		c = pgetc_macro();
147		if (c == PEOF) {
148			if (p == line)
149				return NULL;
150			break;
151		}
152		*p++ = c;
153		if (c == '\n')
154			break;
155	}
156	*p = '\0';
157	return line;
158}
159
160
161
162/*
163 * Read a character from the script, returning PEOF on end of file.
164 * Nul characters in the input are silently discarded.
165 */
166
167int
168pgetc() {
169	return pgetc_macro();
170}
171
172static int
173pread()
174{
175	int nr;
176
177	parsenextc = parsefile->buf;
178retry:
179	if (parsefile->fd == 0 && el) {
180		const char *rl_cp;
181		int len;
182
183		rl_cp = el_gets(el, &nr);
184		if (rl_cp == NULL)
185			nr = 0;
186		else {
187			/* XXX - BUFSIZE should redesign so not necessary */
188			strcpy(parsenextc, rl_cp);
189		}
190
191	} else {
192		nr = read(parsefile->fd, parsenextc, BUFSIZ - 1);
193	}
194
195	if (nr <= 0) {
196                if (nr < 0) {
197                        if (errno == EINTR)
198                                goto retry;
199                        if (parsefile->fd == 0 && errno == EWOULDBLOCK) {
200                                int flags = fcntl(0, F_GETFL, 0);
201                                if (flags >= 0 && flags & O_NONBLOCK) {
202                                        flags &=~ O_NONBLOCK;
203                                        if (fcntl(0, F_SETFL, flags) >= 0) {
204						out2str("sh: turning off NDELAY mode\n");
205                                                goto retry;
206                                        }
207                                }
208                        }
209                }
210		nr = -1;
211	}
212	return nr;
213}
214
215/*
216 * Refill the input buffer and return the next input character:
217 *
218 * 1) If a string was pushed back on the input, pop it;
219 * 2) If an EOF was pushed back (parsenleft == EOF_NLEFT) or we are reading
220 *    from a string so we can't refill the buffer, return EOF.
221 * 3) If there is more in the buffer, use it; else call read to fill it.
222 * 4) Process input up to next newline, deleting nul characters.
223 */
224
225int
226preadbuffer() {
227	char *p, *q;
228	int more;
229	int something;
230	extern EditLine *el;
231	char savec;
232
233	if (parsefile->strpush) {
234		popstring();
235		if (--parsenleft >= 0)
236			return (*parsenextc++);
237	}
238	if (parsenleft == EOF_NLEFT || parsefile->buf == NULL)
239		return PEOF;
240	flushout(&output);
241	flushout(&errout);
242
243again:
244	if (parselleft <= 0) {
245		if ((parselleft = pread()) == -1) {
246			parselleft = parsenleft = EOF_NLEFT;
247			return PEOF;
248		}
249	}
250
251	q = p = parsenextc;
252
253	/* delete nul characters */
254	something = 0;
255	for (more = 1; more;) {
256		switch (*p) {
257		case '\0':
258			p++;	/* Skip nul */
259			goto check;
260
261		case '\t':
262		case ' ':
263			break;
264
265		case '\n':
266			parsenleft = q - parsenextc;
267			more = 0; /* Stop processing here */
268			break;
269
270		default:
271			something = 1;
272			break;
273		}
274
275		*q++ = *p++;
276check:
277		if (--parselleft <= 0) {
278			parsenleft = q - parsenextc - 1;
279			if (parsenleft < 0)
280				goto again;
281			*q = '\0';
282			more = 0;
283		}
284	}
285
286	savec = *q;
287	*q = '\0';
288
289
290	if (parsefile->fd == 0 && hist && something) {
291		INTOFF;
292		history(hist, whichprompt == 1 ? H_ENTER : H_ADD, parsenextc);
293		INTON;
294	}
295
296
297	if (vflag) {
298		out2str(parsenextc);
299		flushout(out2);
300	}
301
302	*q = savec;
303
304	return *parsenextc++;
305}
306
307/*
308 * Undo the last call to pgetc.  Only one character may be pushed back.
309 * PEOF may be pushed back.
310 */
311
312void
313pungetc() {
314	parsenleft++;
315	parsenextc--;
316}
317
318/*
319 * Push a string back onto the input at this current parsefile level.
320 * We handle aliases this way.
321 */
322void
323pushstring(s, len, ap)
324	char *s;
325	int len;
326	void *ap;
327	{
328	struct strpush *sp;
329
330	INTOFF;
331/*dprintf("*** calling pushstring: %s, %d\n", s, len);*/
332	if (parsefile->strpush) {
333		sp = ckmalloc(sizeof (struct strpush));
334		sp->prev = parsefile->strpush;
335		parsefile->strpush = sp;
336	} else
337		sp = parsefile->strpush = &(parsefile->basestrpush);
338	sp->prevstring = parsenextc;
339	sp->prevnleft = parsenleft;
340	sp->prevlleft = parselleft;
341	sp->ap = (struct alias *)ap;
342	if (ap)
343		((struct alias *)ap)->flag |= ALIASINUSE;
344	parsenextc = s;
345	parsenleft = len;
346	INTON;
347}
348
349void
350popstring()
351{
352	struct strpush *sp = parsefile->strpush;
353
354	INTOFF;
355	parsenextc = sp->prevstring;
356	parsenleft = sp->prevnleft;
357	parselleft = sp->prevlleft;
358/*dprintf("*** calling popstring: restoring to '%s'\n", parsenextc);*/
359	if (sp->ap)
360		sp->ap->flag &= ~ALIASINUSE;
361	parsefile->strpush = sp->prev;
362	if (sp != &(parsefile->basestrpush))
363		ckfree(sp);
364	INTON;
365}
366
367/*
368 * Set the input to take input from a file.  If push is set, push the
369 * old input onto the stack first.
370 */
371
372void
373setinputfile(fname, push)
374	char *fname;
375	int push;
376{
377	int fd;
378	int fd2;
379
380	INTOFF;
381	if ((fd = open(fname, O_RDONLY)) < 0)
382		error("Can't open %s", fname);
383	if (fd < 10) {
384		fd2 = copyfd(fd, 10);
385		close(fd);
386		if (fd2 < 0)
387			error("Out of file descriptors");
388		fd = fd2;
389	}
390	setinputfd(fd, push);
391	INTON;
392}
393
394
395/*
396 * Like setinputfile, but takes an open file descriptor.  Call this with
397 * interrupts off.
398 */
399
400void
401setinputfd(fd, push)
402	int fd, push;
403{
404	if (push) {
405		pushfile();
406		parsefile->buf = ckmalloc(BUFSIZ);
407	}
408	if (parsefile->fd > 0)
409		close(parsefile->fd);
410	parsefile->fd = fd;
411	if (parsefile->buf == NULL)
412		parsefile->buf = ckmalloc(BUFSIZ);
413	parselleft = parsenleft = 0;
414	plinno = 1;
415}
416
417
418/*
419 * Like setinputfile, but takes input from a string.
420 */
421
422void
423setinputstring(string, push)
424	char *string;
425	int push;
426	{
427	INTOFF;
428	if (push)
429		pushfile();
430	parsenextc = string;
431	parselleft = parsenleft = strlen(string);
432	parsefile->buf = NULL;
433	plinno = 1;
434	INTON;
435}
436
437
438
439/*
440 * To handle the "." command, a stack of input files is used.  Pushfile
441 * adds a new entry to the stack and popfile restores the previous level.
442 */
443
444STATIC void
445pushfile() {
446	struct parsefile *pf;
447
448	parsefile->nleft = parsenleft;
449	parsefile->lleft = parselleft;
450	parsefile->nextc = parsenextc;
451	parsefile->linno = plinno;
452	pf = (struct parsefile *)ckmalloc(sizeof (struct parsefile));
453	pf->prev = parsefile;
454	pf->fd = -1;
455	pf->strpush = NULL;
456	pf->basestrpush.prev = NULL;
457	parsefile = pf;
458}
459
460
461void
462popfile() {
463	struct parsefile *pf = parsefile;
464
465	INTOFF;
466	if (pf->fd >= 0)
467		close(pf->fd);
468	if (pf->buf)
469		ckfree(pf->buf);
470	while (pf->strpush)
471		popstring();
472	parsefile = pf->prev;
473	ckfree(pf);
474	parsenleft = parsefile->nleft;
475	parselleft = parsefile->lleft;
476	parsenextc = parsefile->nextc;
477	plinno = parsefile->linno;
478	INTON;
479}
480
481
482/*
483 * Return to top level.
484 */
485
486void
487popallfiles() {
488	while (parsefile != &basepf)
489		popfile();
490}
491
492
493
494/*
495 * Close the file(s) that the shell is reading commands from.  Called
496 * after a fork is done.
497 */
498
499void
500closescript() {
501	popallfiles();
502	if (parsefile->fd > 0) {
503		close(parsefile->fd);
504		parsefile->fd = 0;
505	}
506}
507